Process for the washing of fine particles of minerals



A ril 22 1924. 1,491,296-

A. FRANCE PROCESS FOR THE WASHING OF. 'r'iNE PARTICLES, 0F MINERALS Filed March 5. 1921 Illlllllll Ill Illllllllll ND (L Patented Apr. 22, 1924.

UNITED STATES l,49l,296 I PATENT OFFICE.

ANTOINE FRANCE, OF LIEGE, BELGIUM.

Applicationflled March 5, .1921. Serial No. 449,934.

To all whom it may concern:

Be it known that I, ANTOINE FRANCE, 3. subject of the King of the Belgians, residing at Liege, Belgium, have invented certain Improvements in Processes for the Washing of Fine Particles of Minerals, of which the following is a specification. The resent invention relates to a process for the. vashing of fine particles of minerals by means of washing units or sorting pockets with adjustable discharge aperture, arranged in series or parallel series, wherein liquid of high specific gravity is used to effect the sorting.

The use of a series of washing units or of washing units arranged in parallel series,

wherein upwardly directed streams or ascending currents are used to effect the separation, is adapted only for dealing with particles above a certain. minimum diameter, which in the case of coal is about one twelfth of an inch. In such a process, the horizontal classification is efiected by means of a conveying water-stream in a launder or sluice and the vertical classification in washing units or sorting pockets by means of upward streams, so as to obtain the elimination of the high specific gravity particles which proceed along on the layer of schists or slaty material deposited on the bottom of the launder.

For the particles under the aforesaid diameter, the use of ascending streams is without suflicient efiiciency owing to the,ma'-' terial impossibility of obtaining an absolute uniformity of the extremely reduced velocity required. It is in such a case that the use of liquid of high specific gravity instead of the ascending streams in the washing units is indicated.

The process, is still based on the horizontal classification in the launder. I

. It is obvious that if the washing units, or rather their sorting pockets depending from the launder and communicating therewith (the bottom of the launder having suitable slots cut therein for the purpose), are filled with liquid of high specific gravity in a static state up to the level of the bottom of'the launder, the fine particles'having a specific gravity higher than that of the said liquid will drop through the slots provided in the bottom of the launder into the pockets of the washing units, whereas the low s ecific gravity particles will be carried off y the stream of water in the launder.

In fact, in the washing of coal, this result 1s obtained in an automatic and nearly ideal manner by suppressing the. upward streams in the sorting pockets and keeping said pockets continuously filled up to the level of the bottom of-the launder with liquid of high specific gravity conveniently consisting of water containing in suspension the mud which collects on the bottom of the launder, and by adjusting the sectional area of the discharge aperture of the washing units in such a manner that the said liquid of high specific gravity remains in a static or quiescent state.

In such a case it will be desirable to prothe invention may be readily understood, the

same willnow be further described with reference to the accompanying drawing, in

which Fig. 1 is a diagrammatic illustration of one type of mineral washing plant suitable for carrying out the process according to the invention, while Fig. 2 is a diagram- "maticillustration of a modified type of such .plant.

As the liquid of high specific gravity employed in the washing units iswdifl'erent from the liquid used in the launder, the plant for carrying out the aforesaid process should comprise an independent circuit for the liquid'employed in the sorting. apparatus or washing units.

An embodimentv of such an arrangement is, by way of example, shown in Figure 1. The water-stream fed from the tank 4 through the piping 5 takes up and conveys along the launder 3 the products to be sort-' ed which are suppliedby the hopper 1, the discharge opening of which'may be adjusted by means of the'slide-valve 2. The light products are carried right to the end of the launder 3 and are discharged at 7, whence they are removed by means of an elevator 16, while the water passes in the cistern 10 by way of the overflow 12, and is subsequently sent back to thetank 4 by means of the pump 14 and the piping 15. The particles of higher specific gravity sink into the sortin pockets of the washing apparatus 6 arrange along the launder 3, and to which liquld of high specific gravity supplied by the tank 17 is distributed by means of the piping 18, the quantity admitted being so adjusted that the said liquid of high specific gravity will reach the level of the bottom of the launder 3, a water-level gauge 19 being fitted to each sortingpocket to ascertain the said level. The products of specific gravity higher than that of the liquid of high specific gravity filling the sorting pockets of the apparatus 6 are discharged by the latter intosloping launders 2O underneath, leading to a collect- I ing tank 21, whence said products are re moved by means of an elevator 22, while the liquid of high specific gravity passing through the overflow 24 into the cistern 23 is, by means of the pump 25 and the piping 26, sent back to the tank 17, which is provided with an overflow-pipe 17.

This washing process by means of liquid of high spgecific gravity may be advantageously com ined with the washing process in which upward streams are used in the sorting units in cases where the material to be treated consists' mainly of fine particles mixed, however, with particles of such a size as to make it desirable to use upward streams to separate them. In such a case the plant will comprise a series of apparatus usingupward streams to eliminate schists or shales over a certain size, supplemented by a series of sorting apparatus usi a quiespent body of liquid of high specinc gravity to efiect theseparation of the heavy particles under the said size.

An embodiment of such an arrangement is, by way of example, shown in Fig. 2.

' Muddy water containing in suspension a certain proportion of very fine heavy particles is supplied from the tank 17 by means of the plping 18 into the launder'3, wherein the water-stream takes up and carries along the products to be sorted fed by the hopper 2 of which the discharge opening may be adjusted by means 'of the slide-valve 2. A series of washing apparatus are arranged along the launder 3, but while upward streams consistin of muddy water dis.- tributed through t is piping 18 are produced in the first three un1ts6 in the three last units 6' of the series the discharge opening of each of said units is adjusted in such a manner as to obtain in their sorting pockets muddy water in a static state, forming a quiescent body of liquid of high specific gravity containing in suspension mud collecting on the bottom of the launder 3. In this way, only theparticles over a certain diameter will sink through the washing units size which might liavea tendency to follow the heavier particles being sent back into the launder owing to the actlon of the upward streams and mixing with the light particles conveyed towards the washing units 6, through which high specific gravity particles of smaller diameter sink, whereas the light ones are carried off towards the lower end of the sloping launder 3. The'hi h specific gravity minerals discharged'by tie sorting units 6 and 6 drop into the inclined launder 20 arranged under the said units and are then collected in the collecting tank 21, whence they are withdrawn by means of the elevator 22, while the muddy water overflowing through the pipe 24: into the cistern 23 is pumped back by means of the pump 25 and the piping 26 into the tank 17 in order to be used again in the launder 3 and to produce the upward streams in the first three washing unlts 6. The tank 17 is provided with an overflow pipe 17 leading to the cistern 23.

i The above described method of washing fine particles of minerals by means of liquid of high specific gravity may, in the same circumstances than those 'mentioned above, be combined with the washin process with arrangement of the plant in battery and cascade formation and with the washing process wherein mixed material are broughtback to the top of the plant by means of mechanical devices, described respectivelg in my application for U. S. A. patents er, No. 349,119 of February 2nd, 1930, and Ser. No. 360,973 of February 24th, 19 0.

In order to maintain in the tank which supplies the liquid of high specific gravit in a continuous manner a sufiiciently hig specific gravity of the said liquid, the said tank may if desired be gravity gauge which woul register the specific gravit of the said liquid and would itself be fitted with any known suitable device designed to act automatically, electrically or otherwise, u n a valve controllin the supply of a big 1y concentrated liqui contained in a tank situated above the first named tank. In such a case, a blade a itator must be provided in the latter in or er to obtain a rapid dilution'or mixture.

I claim: I

1. The method of separating fine particles rovided with a of minerals of difiering specific gravit-ies cles of highest specific gravity from said 6, the lighter particles or products of smaller quiescent body of liquid.

of minerals of differing specific gravities which consists in stratifying the same in a downwardlyinclined flowing stream of Water, causing the particles of highest specific gravity of the lower stratum of im erfect heavier material to sink into a quiescent body of liquid of high specific gravity, distinct from the aforesaid stream of water, said liquid of high specific gravity being obtained by dilution in water forming said quiescent body of the muddy portion of the aforesaid lower stratum, and withdrawing from said quiescent body of liquid the ma-v terial of highestspecific gravity collecting in the lower portion-thereof.

3. The method of separating fine particles of minerals of differing specific gravities which consists in stratifying the same in a downwardly inclined flowing stream of water, causing the particles of highest specific gravity of the lower stratum of imperfect heavier material to sink at intervals alon said stream into a quiescent body of liquid of high-specific gravity, distinct from such stream, and withdrawing the said particles of highest s ecific gravity from sald quiescent body 0 liquid.

4. The method of separating mineral articles of differing specific gravities W ich consists in stratifying the same in a downwardly inclined conveying stream of water, first removing from the lower stratum of imperfect heavier material the particles of highest specific gravity over a determined size by means of upwardly flowing streams of water meeting the aforesaid conveying stream substantially at right angles, subsequently causing the particles of highest specific gravity of said lower stratum under such determined size to sink at intervals along the conveying stream into aquiescent body of liquid of high specific gravity, distinct from such conveying stream, and withdrawing the last-named particles of highest specific gravity from said quiescent body of liquid. a

In testimony thereof I signed hereunto my name in the presence of two subscribing wit- I nesses.

ANTOINE FRANCE.

Witnesses:

J. Guess, CURTIB 'li. EVERETT. 

